The boxes are actually generally in the form of a flat sheet to be folded subsequently, and are placed on a pallet or flat support, on top of one another, not connected to one another. These boxes then in sheet form can be organized in multiple columns beside one another. It is then necessary to extract from them an upper part to take it into the machine in which the box will be formed. This machine can be a box shaper or have other functions such as packing, for example.
In this field, U.S. Pat. No. 5,102,292 describes, for example, a device that is equipped with a lower shovel that is inserted sideways under the upper batch of sheets to be grasped, while blocks press the batch at the top. The shovel then has a fine enough end for being inserted between the batch and the box under it. The same type of insertion is proposed by US2003/0123962, with the batch being pressed up, however, by means of suction cups. In the two cases, the purpose of the support at the top is essentially to hold the batch to be grasped, while the shovel or blade is inserted between two flat boxes. This force has as its object to prevent the shovel from pushing horizontally the batch to be grasped, which can make the sheets fall.
US2002/0154986 proposes, after the insertion of the blade, inserting along the blade and under it a more rigid sheet that then makes it possible to raise the entire batch. A counter-sheet then clamps the batch. The drawback is that the position of the blade and the position of the more rigid sheet should be the same. It is therefore obligatory to insert the blade where it will be necessary to hold the batch with the clamp that the sheet and the counter-sheet form together.
EP530426 discloses a principle in which the boxes under the batch to be extracted are crushed to make possible the frontal insertion of the shovel.
An insertion of a shovel or blade between two sheets, as taught in these documents, has, however, the drawback of running the risk of bringing the shovel directly against a sheet, which then creates the danger not only of damaging the sheet and actually the sheets against which it abuts, but also to push the pile, and even to cause it to drop completely or in part. Exerting pressure on the top of the column into which the shovel is inserted does not solve the problem of damaging products in the area of the section.
Some embodiments also propose using the pallet in such a way that the columns of sheets come in against vertical support surfaces that oppose a force with the movement of insertion of the shovel for the purpose of stabilizing the column. This type of principle can therefore function only in such an environment and imposes major constraints on the pile itself since it must always be able to come against such a resistance surface.